Diuretic Activity of Compatible Triterpene Components of Alismatis rhizoma

Alismatis rhizoma (AR), the dried rhizoma of Alisma orientale Juzepzuk (Alismataceae), is a traditional Chinese medicine. AR is an important part of many prescriptions and is commonly used as a diuretic agent in Asia. This study aimed to evaluate the diuretic effects of total triterpene extract (TTE) and triterpene component compatibility (TCC, the mixture of alisol B 23-acetate, alisol B, alisol A 24-acetate, alisol A, and alisol C 23-acetate) of AR in saline-loaded rats. The optimal diuretic TCC of AR was optimized using a uniform design. Different doses (5, 20, and 40 mg/kg) of TTE and TCC groups (N1-N8) were orally administered to rats. Urinary excretion rate, pH, and electrolyte excretion were measured in the urine of saline-loaded rats. Results showed that TTE doses increased urine volume and electrolyte excretion compared with the control group. All uniformly designed groups of TCC also increased urine excretion. In addition, optimal diuretic TCC was calculated (alisol B 23-acetate: alisol B: alisol A 24-acetate: alisol A: alisol C 23-acetate 7.2:0.6:2.8:3.0:6.4) and further validated by saline-loaded rats. This study demonstrated that TTE presented a notable diuretic effect by increasing Na⁺, K⁺, and Cl ⁻ displacements. The most suitable TTC compatible proportion of alisol B 23-acetate: alisol B: alisol A 24-acetate: alisol A: alisol C 23-acetate for diuretic activity was validated, and triterpenes were the material basis for the diuretic activity of AR.